From my brief testing, the performance of the latest Intel drivers is significantly better than what shipped in 9.04. Now I'm running 9.04 with a new kernel, xorg edgers, and an old 855GM chip (so there are limitations :-) ) so it's far from what you are testing, but I think the Alpha status should be taken more seriously. Perhaps, as suggested in many places above, test the Intel drivers on another platform.
No announcement yet.
Intel Linux Graphics On Ubuntu Still Flaky